Centrifugal separators

ABSTRACT

A separator includes a vessel having a peripheral wall bounding a chamber. The vessel is rotatable about a rotational axis extending through the vessel. The chamber communicates with an inlet and a first outlet. A tubular member is disposed within the chamber and communicates external thereof. A plurality of fins are disposed within the chamber. Each of the fins extends from toward the tubular member to toward the peripheral wall. A first tube projects from the tubular member to toward the peripheral wall. The first tube has a second outlet in communication with the chamber. The first outlet is disposed closer to the rotational axis than the second outlet such that during use a fluid boundary line first outlet and the second outlet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/056,190,filed Jan. 25, 2002, U.S. Pat. No. 6,719,681, which is acontinuation-in-part of application Ser. No. 09/441,598, filed Nov. 17,1999, U.S. Pat. No. 6,346,069 B1, which claims priority to ProvisionalApplication Ser. No. 60/147,669, filed Aug. 6, 1999. Application Ser.No. 10/056,190 is incorporated herein by specific reference.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to centrifugal separators for separatingfluid components having different densities.

2. The Relevant Technology

Water purification is an age-old activity that has been pursued toachieve both potable water and water for industrial use. With the riseof industrialization, water purification took on a new importancebecause industrial water usage generally involved dischargingcontaminated water into the environment. As concerns about theenvironment have increased, water discharged into the environment hasbeen subjected to increasingly higher standards. Thus, increased effortshave been undertaken to identify methods of processing water tosubstantially reduce both dissolved and particulate pollutants.

One aspect of water purification that is particularly time consumingand/or equipment intensive is liquid-solid separation. Traditionally,settling ponds, or thickeners, have been used in which a large volume ofparticulate-containing water is allowed to reside in a quiescent state.With the force of gravity acting on the mixture, the particulate, eventhose in the Stokes flow regime, will separate from the liquid.

One disadvantage to the use of thickeners is that they have to beextremely large to have any significant flow capacity. Thus, their useis not practical in crowded urban areas where the need for such waterpurification systems is often the greatest. Consequently, thickenershave been developed that allow for a continuous flow ofparticulate-containing liquid into the center of the thickener,producing a clarified supernatant liquid and a compacted sludge. Thecompacted sludge, exiting from the bottom of the thickener, typicallyhas a water content that amounts to between 10 and 30 percent of totalwater being fed to the thickener.

Traditional thickeners have been improved in the last decade or so withthe advent of the high-rate thickener. The high-rate thickener has acenter feed well that extends below the mud line of the underflowmaterial. Accordingly, all water entering the thickener must passthrough the sludge which acts as a filter medium. By using the sludge asa filter, solid-liquid separation rates are increased, albeit onlyincrementally over that of traditional thickeners. Additionally,high-rate thickeners also must be very large and, consequently, alsohave large footprints, rendering their use impractical in manysituations.

Another aspect of separation includes liquid-liquid systems such asseparation the oil and water from a sump in a machine shop or in awashing bay for trains of buses etc. Other liquid-liquid separationsystems are utilized in the food industry where oil and water needseparation. One of the problems in the prior art is the effect of loaddisturbances such as a surge of oil or water in a cleaning operationthat upset the balance of the oil/water feed ratio to the separator.Although the separator may be controlled to prevent one component fromentering the wrong exit stream, a catastrophic surge of one component orthe other cannot be controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed withreference to the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope.

FIG. 1 is a block diagram overview of a process that uses one or more ofthe separators of the present invention;

FIG. 2 is a perspective view of one embodiment of a solid-liquidseparator of the present invention;

FIG. 3 is a cross-sectional view of one embodiment of the solid-liquidseparator shown in FIG. 2;

FIGS. 4A–B are cross-sectional views taken along line 4A—4A and 4B—4B ofFIG. 3, respectively;

FIG. 5 is a perspective view of a partial assembly of the interior ofthe vessel of the solid-liquid separator shown in FIG. 3, revealing aportion of the fin and disc assembly;

FIG. 6 is a perspective view of a partial assembly of the interior ofthe vessel of the solid-liquid separator illustrated in FIG. 3,revealing a more complete portion of the fin and disc assembly;

FIGS. 7A, B and C are alternative fin embodiments which may be utilizedin the separators of the present invention;

FIG. 8 is a perspective view of a partial assembly of the interior ofthe vessel of the solid-liquid separator illustrated in FIG. 3,revealing a completed fin and disc assembly;

FIG. 9 is an elevational cross-sectional view taken along line 9—9 ofFIG. 3;

FIG. 10 is a cross-sectional view of the solid-liquid separatorillustrated in FIG. 3 showing the solid-liquid separator in operation;

FIG. 11 is a cross-sectional view of one embodiment of a liquid-liquidseparator of the present invention;

FIG. 12 is a perspective view of a partial assembly of the interior ofthe vessel of the liquid-liquid separator shown in FIG. 11, revealing aportion of the fin and perforated disc assembly;

FIGS. 13A–13C are block diagrams showing alternative embodiments ofvalve assemblies controlling liquid flow into and out of theliquid-liquid separator;

FIG. 14 is a block diagram showing another embodiment of a valvesassembly controlling liquid flow into and out of the liquid-liquidseparator;

FIG. 15 is a block diagram overview of one process of the presentinvention that uses the liquid-liquid separator in connection with ahydrocyclone;

FIG. 16 is a cross-sectional view of an alternative embodiment of aseparator, wherein the spherical pressure vessel has been replaced witha double frusto-conical pressure vessel;

FIG. 17 is a perspective view of a partial assembly of the interior ofthe vessel of the separator shown in FIG. 16;

FIG. 18 is an elevational side view of an alternative embodiment of aseparator that can function as a solid-liquid and/or liquid-liquidseparator;

FIG. 19 is a cross sectional side view of the separator shown in FIG. 18without the supporting frame;

FIG. 20 is a partially cutaway perspective view of a shaft assembly ofthe separator shown in FIG. 19;

FIG. 21 is a cross sectional side view of the separator taken along line21—21 in FIG. 19;

FIG. 22 is an enlarged cross sectional view of the pressure vessel ofthe separator shown in FIG. 19;

FIG. 23 is a cross sectional side view of an extraction tube of theseparator shown in FIG. 22;

FIG. 24 is a perspective view of a nozzle of the extraction tube shownin FIG. 23;

FIG. 25 is a plan view of a fin of the separator shown in FIG. 22;

FIG. 26 is a perspective view of a fin assembly of the separator shownin FIG. 19;

FIG. 27 is a cross sectional side view of an alternative embodiment ofthe extraction tube shown in FIG. 24;

FIG. 28 is a cross sectional side view of another alternative embodimentof the extraction tube shown in FIG. 24; and

FIG. 29 is a perspective view of a fin assembly of the separator shownin FIG. 19 using solid discs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to systems and corresponding apparatus forclarifying and/or separating components of a fluid stream. For example,in one embodiment, the system can be used for clarifying water or otherliquids that have been contaminated with particulate matter, includingorganic and inorganic contaminants. The system can also be used forseparating immiscible liquids such as an oil/water mixture or separatingliquids of different density. Reference is now made to the drawingswherein like reference numbers refer to like unit operations orstructures. The drawings are understood to be diagrammatic and/orschematic and are not necessarily drawn to scale nor are they to belimiting of the spirit and scope of the present invention.

FIG. 1 is a block diagram overview of one embodiment of a system 8 thatuses an inventive separator as a solid-liquid separator 10 and/or anoil-water separator 22. As illustrated in FIG. 1, separators 10 and 22are connected with a variety of other processing components. System 8 isconfigured for treatment of a fluid feed stream 12 that contains water,oil, and particulate. It is appreciated that depending on the content offluid feed stream 12 and the desired end components, select componentsof depicted system 8 can be removed, exchanged for other apparatus, orthat additional components can be added.

Feed stream 12 may consist of a variety of different compositions, suchas water which includes pollutants like oil, bacterial contaminants,dissolved metals and minerals, and colloidally suspended solids. Feedstream 12 may originate, by way of example and not by limitation, fromindustrial facilities, animal product processing facilities, sewagetreatment, municipal water treatment, the petroleum industry, and anyother type of facility or system that has a fluid product or waste thatneeds to be clarified and/or separated.

Feed stream 12 is initially feed to surge tank 14 which acts as aholding tank to store a large inflow of fluid. Surge tank 14 may includeany commercially available surge tank, an earthen pond, or other liquidholding vessel. In other embodiments, surge tank 14 is not required andcan be eliminated from the system. From surge tank 14, the fluid followsa flow path 16 to a trash strainer 18 for removing trash and oversizedparticles which could clog the system. Exiting from trash strainer 18,the fluid follows flow path 20 into oil-water separator 22 that dividesan oil stream 24 from a water stream 26. As will be discussed below ingreater detail, oil-water separator 22 can also be periodically flushedto clean out particulate matter collected within separator 22. Theparticulate matter is flushed out through a solids line 21 to a filter46 discussed below.

While a variety of oil-water separators may be employed, in oneembodiment oil-water separator 22, as will be discussed below in greaterdetail, is comprised of a separator having many of the same inventivefeatures as will be discussed below with regard to solid-liquidseparator 10. Alternatively, oil-water separator 22 can comprise anoil-water separator such as those separators disclosed in U.S. Pat. Nos.5,387,342, 5,582,724 and 5,464,536.

Water stream 26 may be combined with a filter water stream 28 so as toform a feed stream 29 that is feed to an electrostatic coagulator 32.Electrostatic coagulator 32 operates to electrically sterilize the waterby killing any living organisms, breaking down colloidal suspensions ofimpurities, and coalescing impurities into a flocculent. Such systemsare available from Scott Powell Water Systems, Inc. of Denver, Colo.

A coagulated effluent stream 34 supplies a development tank 36 thattypically has a residence time of from about one to five minutes orlonger. While in development tank 36, the particle size of theflocculent grows. Effluent stream 38 from development tank 36 suppliessolid-liquid separator 10 which will be discussed below in greaterdetail. Solid-liquid separator 10 generates an particulate stream 40constituting the particulate matter and gas that has been removed fromthe effluent stream 38, and a clarified stream 42 constituting theclarified water or other liquid. The clarified water in clarified stream42 is discharged either directly or through a post filter 45 to theenvironment or other designed destination. Particulate stream 40 issupplied to filter 46 from which filter water stream 28 and a filtercake 48 are generated.

In one embodiment, gas and residual oil collected in the top ofdevelopment tank 36 can be directly drawn off through line 49 to filter46. It is also appreciated that oil-water separator 22, electrostaticcoagulator 32, development tank 36, solid-liquid separator 10, andfilter 46 can each be operated under an elevated pressure, such as bythe application of a pump, so as to facilitate desired flows through thesystem. The pressure may vary in one or more of the components 22, 32,36, 10 and 46 so as to control flow in desired directions.

Depicted in FIG. 2 is one embodiment of solid-liquid separator 10incorporating features of the present invention. Solid-liquid separator10 includes a pressure vessel 60 which is driven by a motor 62. Althoughsolid-liquid separator 10 of the present invention can be manufacturedin a variety of different sizes, the depicted embodiment is designed toprocess approximately 40 liters/minute. In such an embodiment, a 2.5horsepower, 3440 RPM electric motor can be utilized.

Pressure vessel 60 is preferably mounted within a guard 64. Guard 64merely provides a shroud or housing as a safety mechanism to keep peopleand objects away from spinning pressure vessel 60. In the illustratedembodiment, a frame assembly 66 is provided to which guard 64 is mountedvia mounting fins 68. One of skill in the art will, of course,appreciate that guard 64 may be configured and attached to frameassembly 66 in a variety of ways.

Frame assembly 66 is further configured to provide support to the motor62 and the bearing structure which supports pressure vessel 60.Solid-liquid separator 10 includes a stationary inlet housing 70configured to receive an inlet line 72. Similarly, a stationary outlethousing 74 is provided on the opposite end of the pressure vessel 60 towhich is attached an outlet removal line 76 and an outlet effluent line78.

A pump 80 is used to receive and feed effluent stream 38 to solid-liquidseparator 10 through inlet line 72. Pump 80 pressurizes effluent stream38 in inlet line 72 such that solid-liquid separator 10 operates undersuch pressure. Hence, pump 80 must be capable of pumping effluent stream38 at the flow rate capacity of the solid-liquid separator 10 whilemaintaining a desired pressure. In one embodiment, pump 80 maintainseffluent stream 38 at a pressure in a range between about 1 psi(6.89×10³ Pa) to about 600 psi (4.14×10⁶ Pa) with about 30 psi (2.07×10⁵Pa) to about 125 psi (8.61×10⁵ Pa) being more preferred. Pump 80 alsoproduces flow rates in a range between about 3 liters/minute to about1,000 liters/minute. Any commercially available pump which can createthe above pressures and the desired flow rates will function for thedesired purpose. Depending on the intended use, it is appreciated thatthe pressure range and flow rate can also be larger or smaller.

As illustrated in FIG. 3, pressure vessel 60 is mounted for rotationabout rotational axis 90 which also coincides with the rotational axisof solid-liquid separator 10. Pressure vessel 60 includes a peripheralwall 92 having an interior surface 93 bounding a chamber 95. In theembodiment depicted, chamber 95 is in the shape of a sphere, althoughother configurations may be utilized. Because vessel 60 is mounted forrotation about axis 90, pressure vessel 60 will generally include ageometry comprising a body of rotation about axis 90.

Additionally, it is desirable, although not required, that the walls ofpressure vessel 60 slope radially outward towards an equator 97 having amaximum diameter that encircles rotational axis 90. Thus, although apressure vessel with spherical walls 92 is one desired embodimentbecause of its efficient pressure bearing qualities, other curved-wallvessels, such as those having an oval, elliptical, or symmetricallyirregular shape may be employed. Furthermore, straight-lineconfigurations such as two truncated cones with their wide ends affixedtogether can be used. Similarly, a vessel having a cylindricalconfiguration at the edges and a center which is formed by truncatedcones connected together can be used. In yet other embodiments, vessel60 need not have outwardly sloping walls. For example, vessel 60 can becylindrical or have a polygonal transverse cross section.

Pressure vessel 60 may be made out of a variety of materials includingstainless steel, plastics, composites, filament wound structures, andother conventional materials. In one embodiment, pressure vessel 60 iscapable of withstanding pressures in a range between about 1 psi(6.89×10³ Pa) to about 2,000 psi (1.38×10⁷ Pa) with about 100 psi(6.89×10⁵ Pa) to about 1,000 psi (6.89×10⁶ Pa) being more preferred. Inthe embodiment depicted, pressure vessel 60 is made out of stainlesssteel and has two halves for ease of manufacture and construction. Thetwo halves are secured together such as by welding, bolts, or otherconventional methods such that a seam is formed at equator 97 of vessel60.

As illustrated in FIG. 3, solid-liquid separator 10 includes a driveshaft 94 at its inlet end 96 which is rigidly mounted to vessel 60.Drive shaft 94 is configured to engage motor 62 (FIG. 2) as is known inthe art. Drive shaft 94 is mounted within a hollow shaft 98 which issecured within inlet mounting collar 100. Inlet mounting collar 100, inturn, is secured to vessel 60 within a plurality of mounting bolts 102,in a manner known to one of skill in the art.

Drive shaft 94, hollow shaft 98, and inlet mounting collar 100 are thusall rigidly secured to each other and to vessel 60 by any of thosemethods known in the art, such as by welding or the use of bolts, suchas mounting bolts 102 which engage an inlet mounting flange 104. Thesecomponents comprise a drive assembly which is rigidly affixed to vessel60 and, consequently, rotates with vessel 60.

The drive assembly is configured to engage inlet housing 70. Inlethousing 70 supports the drive assembly with an inlet bearing assembly106 which, in this embodiment, engages the inlet mounting collar 100.Inlet bearing assembly 106 is a sealed ball bearing assembly resting ina pillow such as will be well known to one of skill in the art.

Inlet housing 70 is configured with a feed stream inlet 114 which isconfigured for receiving inlet line 72 (FIG. 2) via any of those knownattachment methods known in the art for providing fluid communication.As illustrated with reference to FIGS. 3 and 4A, inlet housing 70 isfurther configured with an annular manifold cavity 108 which surroundshollow shaft 98. Hollow shaft 98 includes a plurality of access ports110. Mechanical pump seals 112 are provided between hollow shaft 98 andinlet housing 70 on each side of manifold cavity 108, thereby providinga fluid seal while allowing relative rotational movement between inletstationary housing 70 and hollow shaft 98. Mechanical pump seals such asare available from A. W. Chesterton Co. of Stoneham, Mass. Function forthe desired purpose.

With continued reference to FIG. 3, the support structure for vessel 60at outlet end 120 is illustrated and described. As at inlet end 96,vessel 60 at outlet end 120 is similarly configured with an outletmounting flange 122. An outlet mounting collar 124 is attached to outletmounting flange 122 with a number of bolts 102. Outlet mounting collar124 is supported on outlet housing 74 via an outlet bearing assembly126.

Outlet housing 74 and outlet mounting collar 124 are each configuredwith a hollow interior for receiving an exit tube 128 having a removalchannel 130 therein. As illustrated in FIG. 4B, the hollow interior ofoutlet housing 74 and outlet mounting collar 124 is configured relativeto exit tube 128 such that an annular effluent channel 132 is definedtherebetween. Effluent channel 132 extends exterior of exit tube 128 andis in fluid communication with an effluent outlet 134 configured inoutlet housing 74. Referring again to FIG. 3, in one embodiment effluentoutlet 134 includes a pressure relief valve 136 for maintaining pressurewithin vessel 60. Pressure relief valve 136 may be a one-way,spring-loaded fail shut valve in which the spring force must be overcomeby a sufficient fluid pressure to force the valve open.

An outlet end 129 of exit tube 128 is overfit with mechanical pump seal138. The opposing end of mechanical pump seal 138 is rigidly affixedwithin a circular step configured in the interior end of outlet housing74. Thus, mechanical pump seal 138 acts as a fluid barrier betweenremoval channel 130 and effluent channel 132 and allows for relativerotational movement between exit tube 128 and outlet housing 74. Theoutlet end of outlet housing 74 is further configured with an exitorifice 140 which engages outlet removal line 76. Outlet removal line 76is accessed through an exit valve 148 which may be a standard orsolenoid valve, such as a ball valve that is commercially available.

Exit tube 128 also has an inlet end 131. In one embodiment, a plug 162is received within the opening at inlet end 131. A gas escape orifice164 extends through plug 162 so as to establish fluid communicationbetween the center of chamber 95 and channel 130 extending through exittube 128. Gas escape orifice 164 typically has a diameter in a rangebetween about 0.02 inches (0.05 cm) to about 0.5 inches (1.3 cm) withabout 0.02 inches (0.05 cm) to about 0.125 inches (0.3 cm) being morepreferred. Depending on the intended use, this dimension can also belarger or smaller. In an alternative embodiment, inlet end 131 cansimply be formed with a constricted orifice that communicates withremoval channel 130, thereby precluding the need for plug 162.

With continued reference to FIG. 3, exit tube 128 extends to the centerof vessel 60. Solid-liquid separator 10 also includes a plurality ofradially outwardly extending extraction tubes 160. Each extraction tube160 has a first end 161 and an opposing second end 163. Each first end161 is in fluid communication with exit tube 128 at inlet end 131thereof. Extending through each extraction tube 160 is a channel havinga diameter in a range from about 0.06 inches (0.15 cm) to about 2.0inches (5 cm) with about 0.125 inches (0.3 cm) to about 0.5 inches (1.3cm) being more preferred. In other embodiments the diameter can besmaller or larger. In one embodiment, eight extraction tubes 160 areemployed, each spaced 45 degrees from the adjacent tube. In alternativeembodiments, any number of extraction tubes 160 can be used. In oneembodiment, a typical number of extraction tubes 160 ranges from about 2to about 144 with about 4 to about 24 being more preferred.

In yet another embodiment, extraction tubes 160 need not radiallyoutwardly project from exit tube 128 such that extraction tubes 160 areperpendicular to exit tube 128. Rather, extraction tubes 160 canoutwardly project from exit tube 128 at an angled orientation. Forexample, in one embodiment, the inside angle between each extractiontube 160 and exit tube 128 may be in a range between about 90° to about160°. In the embodiments where the inside angle is greater than 90°,exit tube 128 can be shorter so that inlet end 131 of exit tube 128couples with first end 161 of each extraction tube 160. In yet otherembodiments, the inside angle between each extraction tube 160 and exittube 128 can be less than 90°.

Extraction tubes 160 each extend outwardly an equal distance from therotational axis 90 of solid-liquid separator 10. Each extraction tube160 has an opening 166 at its second end 163 for receiving separatedparticulate matter and fluid. In operation, extraction tubes 160, asfurther explained below, assist in defining a boundary line between thecollected particulate matter and the clarified liquid. Thus, the lengthof extraction tubes 160 is set to provide a predetermined boundary linewithin vessel 60. In one embodiment in which vessel 60 has a maximuminner diameter of 19 inches at equator 97, extraction tubes 160 areconfigured to leave a 0.25 inch (0.65 cm) space between opening 166 intubes 160 and wall 92 of vessel 60. In alternative embodiments,including those of different sized vessels, the space between theopening 166 in extraction tubes 160 and wall 92 of vessel 60 istypically in a range between about 0.125 inches (0.3 cm) to about 2inches (5 cm) with about 0.25 inches (0.6 cm) to about 1 inch (2.5 cm)being more preferred. In other embodiments, the space can be smaller orlarger.

Vessel 60 is also configured with a plurality of fins and discs forchanneling fluid flow through vessel 60. One embodiment of solid-liquidseparator 10 includes a center disc 170, positioned in the center ofvessel 60 and oriented perpendicular to rotational axis 90, asillustrated in FIG. 3. Center disc 170 is configured with a centralorifice which fits over plug 162. Center disc 170 extends in a circularconfiguration radially outward from plug 162. Outer edge 172 of disc 170is circular (following the curvature of vessel 60) and is configured toprovide an axial flow passage 174 between the edge 172 of disc 170 andwall 92 of vessel 60. Flow passage 174 extends annularly about axis 90.Outer edge 172 is typically, although not necessarily, disposed radiallyinward from opening 166 of extraction tubes 160. In one embodiment, thedistance between edge 172 of disc 170 and wall 92 of vessel 60 is in arange between about 0.5 inches (1.3 cm) to about 4 inches (10 cm) withabout 0.8 inches (2 cm) to about 1.2 inches (3 cm) being more preferred.In other embodiments, this distance can also be larger or smaller.

The depicted embodiment also includes four additional discs 176, 178,202 and 204. Discs 176 and 202 are positioned on the inlet side ofvessel 60 with discs 178 and 204 positioned on the outlet side. Discs176, 178, 202 and 204 are used in part to facilitate assembly of thesolid-liquid separator 10 and to provide structural support duringoperation thereof. Alternatively, the solid-liquid separator 10 can beassembled with fewer or greater numbers of assembly discs. It is alsoenvisioned that the inventive solid-liquid separator 10 can beconstructed without discs by securing the fins, as discussed below,directly to exit tube 128 and/or wall 92 of vessel 60.

As illustrated in FIGS. 5 and 6, discs 176 and 202 include centralorifices 180 which allow gas that collects at the center of the vessel60 to be extracted. Discs 178 and 204 are similarly configured withcentral orifices 182 slightly larger than the outside diameter of exittube 128, thereby accommodating passage therethrough of exit tube 128.V-notches 210 may be formed, such as by being laser cut, into outer edge172 of disc 170. These v-notches minimize the disturbance of thecollected particulate matter as the clarified water flows around disc170. In one embodiment, these v-notches 210 are cut at the edge 172 ofdisc 170 having a width in a range between about 0.1 inch (0.25 cm) toabout 1 inch (2.5 cm) and a depth in a range between about 0.1 inch(0.25 cm) to about 1 inch (2.5 cm). The number of v-notches 210 that arecut into center disc 170 between each pair of fins 184 is typically in arange between about three notches to about eight notches. Alternatively,the number and size of these v-notches 210 can be increased or reduced.

Referring now to FIG. 5, solid-liquid separator 10 also includes aplurality of radial fins 184. Each fin 184 has an inside edge 186 whichis generally parallel to rotational axis 90 and an outside edge 188which generally follows the curvature of vessel 60. Thus, in theconfiguration illustrated herein, in which spherical vessel 60 isemployed, outside edge 188 of fins 184 has a substantially semi-circularconfiguration.

In the embodiment illustrated in FIG. 8, two types of fins 184 are used:trimmed fins 212 and untrimmed fins 214. As depicted in FIG. 7A, eachtrimmed fin 212 includes a substantially flat inside edge 186 and anopposing outside edge 188. Outside edge 188 includes a substantiallyflat side portion 187 orthogonally projecting from each end of insideedge 186, a centrally disposed substantially flat nose portion 189disposed substantially parallel to inside edge 186, and a curvedshoulder portion 191 extending from each side portion 187 to opposingends of nose portion 189.

As illustrated in FIG. 7B, each untrimmed fin 214 includes asubstantially flat inside edge 186 and an opposing outside edge 188.Outside edge 188 includes a substantially flat side portion 187orthogonally projecting from each end of inside edge 186 and a curvedface portion 193 extending between each side portion 187. A centrallydisposed semi-circular notch 194 is formed on face portion 193.

An alternative fin 215 is illustrated in FIG. 7C. Fin 215 hassubstantially the same configuration as untrimmed fin 214 except thatnotch 194 is replaced with holes 196 extending through fin 215. Suchholes 196 typically have a diameter in a range between about 0.5 inches(1.3 cm) to about 1.5 inches (3.8 cm).

Fins 184 are positioned within chamber 95 of vessel 60 perpendicularlyto discs 170, 176, 178, 202 and 204 as best illustrated in FIGS. 5 and6. Each disc is provided with a slot 198 which corresponds to each fin184. Slots 200, which correspond to each disc 170, 176, 178, 202 and204, are also configured in each fin 184. Fins 184 and discs 170, 176,178, 202 and 204 are in one embodiment formed of stainless steel but canalso be formed from plastics, composites, and other sufficiently strongmaterial. Slots 198 and 200 may be formed using any conventional methodsuch as by laser cutting. Slots 198 and 200 are configured to allow thefins and discs to engage each other in a slip fit, mating relationship.Thus, slots 198 configured in discs 170, 176, 178, 202 and 204 have awidth at least as great as the thickness of fins 184. Similarly, slots200 configured in fins 184, have a width at least as great as thethickness of the discs 170, 176, 178, 202 and 204 which correspond tothese slots.

The fin and disc assembly within vessel 60 is thus assembled asillustrated in FIG. 5 by positioning outlet discs 204 and 178 over exittube 128. Center disc 170 as seen in FIG. 6 is then placed about plug162 and some fins 184 are engaged into their corresponding slots on thediscs 170 and 178 while simultaneously engaging the discs with thecorresponding slots on fins 184. When fin 184 is thus placed into matingengagement with a disc, virtually all relative movement between the discand the fin is prohibited. Inlet discs 176 and 202 are then placed intomating engagement with slots 200 on fins 184. With all five discs 170,176, 178, 202 and 204 now in position, the remaining fins are installedby sliding them radially into position, until the interior configurationof the vessel 60 is complete as illustrated in FIG. 8. Slots 198 and 200are simply one way of securing the fins and discs together. Inalternative embodiments, the fins and discs can be welded, clamped,integrally molded, or otherwise secured together using conventionalmethods.

In the depicted embodiment, twenty four fins 184 are utilized in vessel60, as illustrated in FIGS. 8 and 9. In alternative embodiments, thenumber of fins 184 is typically in a range between about 8 to about 144with about 12 to about 48 being more preferred. As best depicted inFIGS. 3, 8, and 9, the assembled fins 184 radially outwardly projectfrom rotational axis 90 in substantially parallel alignment withrotational axis 90. Each inside edge 186 is spaced apart from the centerof rotational axis 90 so that a channel 219, depicted in FIG. 3, isformed that extends from inlet end 96 to gas escape orifice 164. Channel219 has a diameter typically in a range between about 0.25 inches (0.6cm) to about 2 inches (5 cm) with about 0.25 inches (0.6 cm) to about 1inch (2.5 cm) being more preferred. Depending on the intended use, thediameter can also be smaller or larger. As illustrated in FIGS. 7A and7B the inside edge 186 of each fin 184 is cut to prevent interferencewith exit tube 128 and gas escape plug 162.

To accommodate the eight radial extraction tubes 160, trimmed fins 212are modified with a central notch 216 as illustrated in FIG. 5. Notch216 is sized to allow some degree of intersection of trimmed fins 212with extraction tubes 160, as illustrated in FIG. 9. Hence, in thedepicted embodiment, sixteen trimmed fins 212 as modified with a notch216 are utilized in combination with eight untrimmed fins 214 which havenot been so modified.

In an alternative embodiment, it is appreciated that fins 184 need notradially outwardly project in alignment with rotational axis 90. Rather,inside edge 186 of each fin 184 can be offset from alignment rotationalaxis 90 and still be retained in position by the discs. As used in thespecification and appended claims, the phrase, “fin projecting fromtoward the rotational axis” is broadly intended to include embodimentswhere an inside edge of a fin is disposed in a plane that is eitheraligned with or offset from the rotational axis, where at least aportion of the inside edge is directly disposed along the rotationalaxis or is radially spaced outward from the rotational axis, and/orwhere the inside edge is parallel with or angled relative to therotational axis.

With the fins and discs assembled about exit tube 128 as illustrated inFIG. 8, the internal assembly is enclosed within chamber 95 of vessel60. In one embodiment, vessel 60 is comprised of two halves which aresecured together, such as by welding or bolting with a seal such as agasket or o-ring disposed therebetween. By covering the internalassembly of FIG. 8 within wall 92 of vessel 60, the fins and discsbecome locked to each other in relative engagement and no welding isneeded to hold them secure.

Specifically, as depicted in FIG. 10, flat side portions 187 of each fin184 are disposed adjacent to mounting flanges 104 and 122. Curvedshoulder portions 188 of trimmed fins 212 are disposed adjacent to wall92. Similarly, curved face portion 193 of untrimmed fins 214 are alsodisposed adjacent to wall 92. Side portions 187, shoulder portions 188,and face portion 193 of fins 184 can be directly biased against vessel60. Alternatively, a small gap, typically less than about ¼ inch, can beformed between vessel 60 and portions 187, 188, and 193. As illustratedin FIG. 9, the positioning of fins 184 adjacent to wall 92 results inthe formation of a plurality of discrete flow channels 218 throughvessel 60 along the rotational axis. Each flow channel 218, however, ispartially blocked by the intersection of the various discs 170, 176,178, 202, and 204. As a result of the discs, fluid traveling throughflow channels 218 is required to flow around the outer edge of thediscs.

Returning to FIG. 10, an underflow passage 190 is formed between flatnose portion 189 of trimmed fins 214 and wall 92. Underflow passage 190enables fluid to flow between discrete flow channels 218 at equator 97.In one embodiment, the maximum gap between flat nose portion 189 oftrimmed fin 214 and wall 92 is in a range between about 0.125 inches(0.3 cm) to about 2 inches (5 cm) with about 0.25 inches (0.6 cm) toabout 1 inch (2.5 cm) being more preferred. In other embodiments, themaximum gap can be larger or smaller. Although not required, in oneembodiment flat nose portion 189 of each fin 184 is positioned radiallyinward from opening 166 of each corresponding extraction tube 160.

It is of course envisioned that fins 184 can be formed in a variety ofdifferent configurations to facilitate underflow passage 190 betweenflow channels 218. For example, trimmed fins 212 can be replaced withalternative fins 215. In this embodiment, holes 196 facilitate underflowpassage 190. In yet other embodiments, notches, slots, holes, grooves,and the like can be formed in a fin 184 to facilitate underflow passage190.

Notch 194 (FIG. 7B) formed in untrimmed fins 214 is designed to performtwo functions. First, in an embodiment where a seam is formed at equator97, such as an inside flange, notch 194 provides space to receive theseam. Notch 194 also functions to allow at least some flow between flowchannels 218 separated by untrimmed fins 214. Fluid flow through notch194 thus helps to insure that boundary layers and flow rates are thesame in each flow channel 218.

Once the internal assembly is enclosed within vessel 60, the inlet andoutlet mounting collars 100, 124, the bearing assemblies, and housingsassembled as described above are bolted or otherwise secured to vessel60 using conventional methods known to those skill in the art.

In operation, as illustrated in FIG. 2, rotation of the vessel 60 iscommenced by turning on motor 62. Motor 62 typically causes vessel 60 torotate with a rotational velocity in a range between about 600rotations/minute to about 10,000 rotations/minute with about 1,200rotations/minute to about 3,600 rotations/minute being more preferred. Astream 38 is received by pump 80 which pumps stream 38 into thesolid-liquid separator 10 through inlet line 72. Stream 38 is preferablypressurized by pump 80 such that a hydraulic pressure is maintainedwithin vessel 60 during operation of the solid-liquid separator 10. Inone embodiment vessel 60 of solid-liquid separator 10 operates under ahydraulic pressure in a range between about 1 psi (6.89×10³ Pa) to about600 psi (4.14×10⁶ Pa) with about 30 psi (2.07×10⁵ Pa) to about 125 psi(8.61×10⁵ Pa) being more preferred. Depending on the intended use, therotational velocity and operating pressure can be greater or smaller.

In addition to the hydraulic pressure applied to vessel 60 by stream 38,a centrifugal force is applied to stream 38 and vessel 60 as a result ofthe rotation of vessel 60. This centrifugal force increases as thedistance away from rotational axis 90 increases. As such, the totalforce at the perimeter of vessel 60 may be several times that of thehydraulic pressure.

Stream 38 may include virtually any liquid which has been contaminatedwith a particulate component having a density greater than the liquid.For most applications, however, the liquid will be water. Thus, althoughwater is referred to herein as the liquid being clarified, it will beunderstood that solid-liquid separator 10 of the present invention maybe used to clarify a variety of liquids.

As illustrated in FIG. 10, feed stream 38 enters the solid-liquidseparator 10 through feed stream inlet 114. As feed stream 38 reachesthe rotating hollow shaft 98, it is forced through access ports 110 (seealso FIG. 4) into the hollow shaft 98 where the stream is accelerated tothe same rotational velocity as vessel 60. Flow through rotating hollowshaft 98 proceeds in the direction of arrow A. Upon reaching theentrance to vessel 60 adjacent inlet mounting flange 104, thecentrifugal force imposed due to the rotation of vessel 60 pushes thestream radially outwardly towards wall 92 of vessel 60. As the streamenters vessel 60, it enters one of the flow channels 218 (FIG. 9) andproceeds to fill vessel 60.

Flow channels 218 help eliminate the Coriolis effect. That is, if fins184 were removed, as the fluid enters vessel 60, the fluid would swirlin a vortex. Such swirling produces a turbulent flow that suspendsparticles within the fluid. As discussed below, in one embodimentsolid-liquid separator 10 operates by settling the particulate matteragainst or adjacent to wall 92 of vessel 60 from where it issubsequently removed. By passing the fluid through discrete flowchannels 218, swirling of the fluid is substantially eliminated. Thefluid travels in a substantially laminar flow wherein the fluid rotatesat the same speed as vessel 60. As a result, the potential for settlingparticulate within the liquid is maximized.

As stream 38 enters the vessel, it is forced around disc 176 along thedirection of arrows B. Within vessel 60, the stream is subjected to thetremendous centrifugal forces imposed on it due to the rotation ofvessel 60. Thus, the more dense component of the stream, i.e., theparticulate matter, flows radially outwardly while the less densecomponent flows radially inwardly or stays on top. In one embodiment,the centrifugal forces present in solid-liquid separator 10 produce anaverage of approximately 500 g to about 2,000 g's on the fluid mixture.The centrifugal force rapidly clarifies the fluid producing a low liquidcontent of the more dense particulate matter. Solid-liquid separator 10can thus achieve in minutes or seconds the amount of separation that astatic tank separator takes hours to achieve.

As discussed above, the particulate matter in stream 38 is forced by therotation of vessel 60 to accumulate against wall 92 at equator 97. Theaccumulated particulate matter is identified as collected solids 224. Aboundary line 228 is defined between collected solids 224 and theclarified water 226 radially inwardly disposed therefrom. Collectedsolids 224 are allowed to accumulate and boundary line 228 rise untilboundary line 228 is located radially inward of opening 166 ofextraction tubes 160 (a condition illustrated in FIG. 10). Collectedsolids 224 are subsequently extracted from pressure vessel 60 throughextraction tubes 160 as described below.

Water flowing around the edge of disc 170 through axial flow passage 174can stir up collected solids 224 that have settled at the largestdimension radius or equator 97 of pressure vessel 60. Although notalways, in one embodiment this stirring caused by eddy effects works inopposition to the purpose of solid-liquid separator 10. Therefore,notches such as v-notches 210 previously discussed with regard to FIG. 6may be cut in the outer perimeter of disc 170. The notches minimizestirring by reducing the force of the water flow around disc 170,thereby reducing the eddy effects. Thus the v-notches 210 maintainboundary layer 228 between collected solids 224 and clarified water 226.

Apart from functioning to support fins 184, the various discs,particularly disc 170, function to assist in the removal of theparticulate matter. That is, all fluid that enters vessel 60 must floweither to or around the outer edge of disc 170 before it can exit vessel60. By forcing all of the fluid to flow to the outer edge of disc 170 atequator 97, all of the fluid is subject to the greatest centrifugalforce produced by the rotation of vessel 60, thereby ensuring that thehighest concentration of particulate matter is removed from the incomingfluid. Discs 176 and 178 also function for this purpose. Furthermore, bypositioning discs 176 and 178 on opposing sides of disc 170, the fluidflows radially inward and outward as it moves between the discs. Thisradial movement of the fluid increases the retention time of the fluidwithin the vessel, thereby subjecting the fluid to the centrifugal forceof the vessel for a longer period of time. As a result, a larger portionof the particulate matter is removed. In an alternative embodiment,however, the inventive solid-liquid separator can be operated withoutthe use of the discs, particularly disc 170.

Because gases may occasionally be found in fed stream 38, a gas layer230 may form about axis 90 on the inlet side of vessel 60. Disc 170effectively serves as a barrier between the inlet side and the outletside of vessel 60. Hence, gases found within the feed stream willgenerally be found only on the inlet side of vessel 60 because they arelikely to be separated before the liquid passes through axial flowpassage 174.

As feed stream 38 continues to flow into the vessel 60, the fluid passesaround the outer perimeter of center disc 170 and into the outlet sideof vessel 60. Clarified water 226, which can be other fluids in otherembodiments, fills the outlet side of vessel 60 and then flows outthrough effluent channel 132. Clarified water 226 subsequently exitssolid-liquid separator 10 through effluent outlet 134 and pressurerelief valve 136. Pressure relief valve 136 only opens when the backpressure in effluent outlet 134 overcomes the spring force for thevalve, thereby ensuring that a predetermined pressure is maintainedinside vessel 60. In an alternative embodiment, pressure relief valve136 can be replaced with other operating systems that perform the samefunction. For example, pressure relief valve 136 can be replaced with anelectronically operated valve and a pressure sensor. The valve iselectronically opened when the pressure sensor senses a predeterminedpressure within vessel 60 or outlet 134. In other embodiments, valve 136can be self-adjusting so as to allow clarified water 226 to continuallyflow therethrough at a given pressure. Should the flow increase ordecrease, valve 136 automatically opens or closes a proportional amountso that the pressure is held substantially constant.

Boundary line 228 is maintained at a desired level by periodicallyopening valve 148 and allowing collected solids 224 to be extractedthrough extraction tubes 160. When valve 148 is opened, a pressuregradient is created between the interior of vessel 60 and outlet removalline 76. Flow of collected solids 224 proceeds from the higher pressureenvironment within vessel 60 to the lower pressure through extractiontubes 160. This pressure differential may be created a number of ways,such as by operating vessel 60 at ambient pressure and imposing anegative pressure on extraction tubes 160, or, as is presently depicted,operating vessel 60 under pressure and imposing extraction tubes 160 toa near ambient pressure.

Recognizing that the eight extraction tubes 160 only extend into eightof the flow channels 218 (FIG. 9), boundary line 228 drops in these flowchannels 218 as collected solids 224 are extracted. As boundary line 228in these flow channels 218 drops, collected solids 224 from adjacentflow channels 218 flows through underflow passage 190 to maintainboundary line 228 at a generally constant level throughout thecircumference of vessel 60. In an alternative embodiment, it isenvisioned that an extraction tube 160 can be feed to each discrete flowchannel 218. In this embodiment, it is not necessary to have underflowpassage 190 between flow channels 218, i.e., fins 184 can extend all theway to wall 92 of vessel 60 along the length of fins 184.

When exit valve 148 is opened, any gas which has built up inside vessel60 to form a gas layer 230 will immediately begin escaping throughorifice 164 of plug 162 which is in fluid communication with removalchannel 130. Thus, orifice 164 should preferably be sized such that anyanticipated gas buildup may be removed through the periodic opening ofvalve 148. Orifice 164, however, should be sufficiently small so as toenable sufficient draw on extraction tubes 160 to remove collectedsolids 224. Thus, the size of orifice 164 depends in part upon theconstituency and nature of the fluid flow. In one embodiment, orifice164 has a threaded diameter of approximately 0.375 inch (1 cm). This0.375 inch (1 cm) orifice is threaded to allow an insert whereby theorifice diameter may be reduced or even totally occluded, depending uponthe insert selected. An insert may be threaded into orifice 164 evenafter construction of the pressure vessel 60 because orifice 164 remainsaccessible through exit orifice 140 and removal channel 130. Theadjustable nature of this orifice diameter allows orifice 164 to betailored for different fluid flows while using the same solid-liquidseparator 10.

In one embodiment of the present invention, spherical vessel 60 has aninside diameter of about 19 inches (48 cm) and is capable of processingapproximately 38 liters of water each minute. This provides a residencetime of approximately 1.5 minutes in solid-liquid separator 10 whilesubjecting the water to an average of approximately 700 g forces. Thisis roughly the equivalent of 2 hours of residence time in a staticclarifier having the same capacity. In one embodiment, the solid-liquidseparator is capable of clarifying water to remove at least 99% ofsolids. In alternative embodiments, the present invention envisions thattypical vessels can be formed having a maximum inside diameter in arange between about 6 inches (15 cm) to about 120 inches (300 cm) withabout 12 inches (30 cm) to about 60 inches (150 cm) being morepreferred. Such vessels can be designed to process fluid at a rate in arange from about 0 liters/minute to about 4,000 liters/minute with about1 liter/minute to about 1,000 liters/minute being more preferred. It isappreciated that in other embodiments, the above variables can be largeror smaller.

The resulting particulate stream 40 is passed through a bag filter,filter press, and/or belt filter to remove remaining water and to “cake”the solids. The “caked” solids may then be disposed of by composting orother method known in the art. Ultimately, the disposal method willdepend upon the composition of the “caked” solids. For instance, solidscontaining heavy metals cannot be composted and other appropriatedisposal methods will be used.

To shut down solid-liquid separator 10, the pump and motor are turnedoff, then vessel 60 is drained and flushed. Alternatively, fluid maysimply be left within the vessel 60 during non-use.

In one embodiment, depending on the operating parameters and theparticle matter being collected, collected solids 224 can be difficultto fully extract from vessel 60 through extraction tubes 160. Forexample, collected solids 224 can be caked on wall 92 to such an extentthat they do not freely flow into extraction tubes 160. In one approachto more easily and fully removing collected solids 224, the inflow ofstream 38 to vessel 60 and the outflow of clarified water 226 fromvessel 60 can be momentarily stopped. While vessel 60 continues torotate, a removal stream can be pumped into removal channel 130 of exittube 128 so that the removal stream passes down through extraction tubes160 and into vessel 60.

As the removal stream passes into vessel 60, the removal streamresuspends the caked solids into surrounding fluid. The centrifugalforce, however, keeps the particulate matter substantially adjacent toperimeter wall 92. Once the particulate matter is resuspended in a lessdense phase, extraction tubes 160 can return to their original operationwhere the fluid containing the resuspended particulate matter is drawnout of vessel 60 through extraction tubes 160 and exit tube 128. Once adesired amount of the particular matter is removed, flow throughextraction tubes 160 can be closed while rotating vessel 60 resettlesthe particulate matter against peripheral wall 92. Once the particulatematter is sufficiently settled, feed stream 38 and clarified water canagain flow into and out of vessel 60.

As will be discussed below in greater detail different forms of nozzlescan be placed at then end of extraction tubes 160 for more efficientlyresuspended the particulate matter. Furthermore, a separate tube can beused to deliver the removal stream into vessel 60.

Depicted in FIGS. 11 and 12, another embodiment of the present inventionrelates to a liquid-liquid separator 244 that uses a similarconstruction to solid-liquid separator 10 depicted in FIGS. 2–10. Incontrast to solid-liquid separator 10 that is primarily designed toremove particulate from a fluid, liquid-liquid separator 244 isprimarily designed to separate a mixed liquid of two or more immiscibleliquids such as oil and water or any other types of immiscible liquids.Liquid-liquid separator 224 can thus be used as oil-water separator 22.

FIG. 12 illustrate a subassembly 232 of liquid-liquid separator 244.Subassembly 232 includes a solid inlet side minor disk 234 similar toinlet side minor disk 176 depicted in FIG. 6. A center disk 236 isdepicted as having a plurality of perforations 238. Perforations 238allow for the passage of the liquids therethrough. Additionally, anoutlet side minor disk 240 is also depicted as having a plurality ofperforations 238 extending therethrough.

As depicted in FIG. 11, the remainder of subassembly 232 and the vesselin which subassembly 232 is disposed are substantially the same as thatpreviously discussed with regard to solid-liquid separator 10. As such,like elements are identified by like reference characters. Furthermore,the alternatives discussed above with regard to solid-liquid separator10 are also applicable to liquid-liquid separator 244.

Liquid-liquid separator 244 also operates in a manner similar tosolid-liquid separator 10. For example, with vessel 60 rotating, themixed liquid is pumped into inlet 114 so as to flow down hollow shaft 98along arrow A. Upon reaching the entrance to vessel 60, the mixed liquidenters one of the flow channels 218 (FIG. 9) and proceeds to fill vessel60. As a result of the centrifugal force produced by the rotation ofvessel 60 and the impact of the mixed liquid against minor disk 234, themixed liquid is pushed radially outwardly towards wall 92 of vessel 60and around disk 234.

The mixed liquid includes a heavy component 241 and a light component243 which are defined by their relative densities. It is appreciatedthat heavy component 241 may also include comprise particulate matter.Where the mixed liquid includes more than two immiscible liquids, heavycomponent 241 or light component 243 can be defined to include more thanone liquid. The drawn off liquid that includes more than one liquid cansubsequently be processed through a second liquid-liquid separator 244so as to separate the liquids therein.

As a result of the applied centrifugal force, heavy component 241 flowstoward wall 92 at equator 97. Light component 243 flows toward thecenter or rotational axis 90 of vessel 60. As a result, a boundary line245 is formed between heavy component 241 and light component 243.Boundary line 245 is maintained within a range of radial distances awayfrom rotational axis 90. This liquid-liquid boundary line 245 isanalogous to boundary line 228 depicted in FIG. 10 for solid-liquidseparator 10. In contrast, however, liquid-liquid boundary line 245 istypically positioned at a radial distance from rotational axis 90 in arange from about ⅕ to about ⅘ the distance between rotational axis 90and the maximum diameter at equator 97, preferably from about ¼ to about¾ the distance, even more preferably from about ⅓ to about ⅔ thedistance. In other embodiments, the distance can be smaller or larger.

As a result of perforations 238 extending through discs 236 and 240,light component 243 and gas 230 can flow through discs 236 and 240 andout effluent channel 132. Since gas 230 exits with light component 243,there is no need for a gas escape orifice at inlet end 131 of exit tube128. In this embodiment, discs 236 and 240 function primarily assupports for fins 184 and thus can be any desired configuration.Alternatively, discs 236 and 240 can be removed.

Heavy component 241 is removed from vessel 60 through extraction tubes160 and exit tube 128. Where there are fewer extraction tubes 160 thandiscrete flow channels 218, underflow passages 190 are formed betweendiscrete flow channels 218 so that boundary line 245 is constant for allflow channels 218. Since boundary line 245 is typically closer torotational axis 90 than boundary line 189, second end 163 of extractiontubes 160 can be moved closer to rotational axis 90.

In one embodiment of the present invention, means are provided forpressurizing the fluid within pressure vessel 60 so as to automaticallycontrol the position of boundary line 245 within pressure vessel 60 asthe ratio of light component and heavy component of the fluid enteringpressure vessel 60 changes. Several alternative examples of such meansare described below. By way of example and not by limitation, depictedin FIGS. 11 and 13A is one embodiment of a control system 290 forremoving the separated liquids from liquid-liquid separator 244.Specifically, a supply stream 30 containing two immiscible liquids isfed to liquid-liquid separator 244 where the two liquids are separatedwithin pressure vessel 60 into heavy component 241 and light component243 as discussed above. Control system 290 includes a first valve 248coupled with effluent line 78 and a second valve 256 coupled withremoval line 76.

According to the present invention, a pressure differential ismaintained between first valve 248 and second valve 256. The pressuredifferential is needed to maintain boundary line 245 at a defined radialdistance from rotational axis 90 such that only light component 243exits through effluent channel 132 and effluent line 78 and only heavycomponent 241 exits through extraction tubes 160, exit tube 128, andremoval line 76. Failure to establish and maintain a pressuredifferential between valves 248 and 256 can result in boundary line 245extending beyond extraction tubes 160 such that a portion of lightcomponent 243 exits with heavy component 241 through extraction tubes160 or can result in boundary line extending into effluent channel 132such that a portion of heavy component 241 exits with light component243 through effluent channel 132.

The pressure differential is based on the operating properties ofseparator 244, such as rotational velocity, and the material propertiesof supply stream 30, such as the density and viscosity of the at leasttwo immiscible liquids contained within supply stream 30. The pressuredifferential is also based on the desired location of boundary line 245within vessel 60. It is appreciated that in some embodiments thepressure differential can be zero or substantially zero so as tomaintain boundary line 245 at the desired location.

In practice, the pressure differential can be empirically determined.For example, initially first valve 248 is set to operate at a firstpressure. That is, first valve 248 maintains the exiting light component243 at the first pressure while enabling exiting light component 243 tocontinually flow through first valve 248. Accordingly, if the flow ofexiting light component 243 decreases, first valve 248 automaticallycloses a corresponding amount so as to maintain the first pressure. Inthis regard, first valve 248 can comprises a back-pressure regulatorsuch as a Fisher 98L made by Fisher Controls International, Inc., out ofMarshall Town, Iowa. Alternatively, first valve 248 can comprise apiloted or controlled back-pressure regulator, also available from byFisher Controls International, Inc., which operates in communicationwith a pressure sensor 246 coupled effluent line 78. In either the aboveembodiments or other alternative valve configurations, first valve 248is configured to automatically adjust so as to maintain a desiredpressure on exiting light component 243 as the flow rate thereofchanges. Where the flow rate is substantially constant, first valve 248can be configured for manual rather than automatic adjustment.

The amount of first pressure is in some regards arbitrary since it isthe pressure differential that controls the position of boundary line245. In one embodiment, however, first pressure is typically in a rangebetween about 1 psi (6.89×10³ Pa) to about 600 psi (4.14×10⁶ Pa) withabout 30 psi (2.07×10⁵ Pa) to about 125 psi (8.61×10⁵ Pa) being morepreferred. In other embodiments, the pressure can be greater or smaller.

Once the first pressure for first valve 248 is set, second valve 256 isinitially set to operate at the same pressure. Liquid-liquid separator244 is then operated at a flow rate for supply stream 30 and at adefined rotational velocity for vessel 60. The operating pressure forsecond valve 256 is then incrementally varied in opposite directions soas to determine the extreme operating pressures for second valve 256.For example, the operating pressure for second valve 256 can beincrementally decreased and then incrementally increased so as todetermine the pressures for second valve 256 at which light component243 first starts to flow out of removal line 76 with heavy component 241and heavy component 241 first starts to flow out of effluent line 78with light component 243.

Once the two extreme operating pressures for second valve 256 aredetermined, second valve 256 is set to operate at a pressure between thetwo extreme pressures. This places boundary line 245 substantiallycentrally between the opening to effluent channel 132 and opening 166 toextraction tubes 160. Alternatively, second valve 256 can be set tooperate at any desired pressure between the two extreme pressures. Theresulting pressure difference between first valve 248 and second valve256 defines the pressure differential. Second valve 256 can comprise thesame type of valves as discussed above with regard to first valve 248.As such, in one embodiment, second valve 256 can operate in conjunctionwith a pressure sensor 252 coupled with removal line 76.

One of the unique benefits of the inventive system is its ability tocompensate for changes in the ratio of the two immiscible liquids insupply stream 30. For example, assuming an oil/water supply stream 30feeds liquid-liquid separator 244 at a 50/50 mixture. At a given time,the 50/50 mixture suddenly experiences a load change to 10% oil and 90%water. Where the rotational velocity of liquid-liquid separator 244remains substantially constant, an increased amount of water (heavycomponent 241) will tend to cause boundary line 245 to move towardrotational axis 90. Accordingly, the pressure sensed at first valve 248will decrease while the pressure sensed at second valve 256 willincrease. As a result, second valve 256 will automatically closeslightly and first valve 248 will automatically open slightly. As aresult, the operating pressures for valves 248 and 256 and the pressuredifferential between valves 248 and 256 are continually held relativelyconstant even though the ratio of liquids in supply stream 30 maycontinually change. As such, the position of boundary line 245 is heldrelatively constant within vessel 60.

A 100% water supply stream 30 or a 100% oil supply stream 30 may also becontrolled by maintaining boundary line 245 within the preferreddistance range from rotational axis 90. For example, where a 100% oilsupply stream 30 is fed to liquid-liquid separator 244, second valve 256will eventually shut entirely in order to maintain the liquid-liquidinterface within the preferred distance range away from rotational axis90. Accordingly, where all liquid in supply stream 30 is oil, the oilwill move through liquid-liquid separator 244 substantially without anymixing with the water that, under this situation, would be substantiallystagnant therein.

Another embodiment of a control system 294 is depicted in FIG. 13B. Likeelements between control system 290 and 294 are depicted by likereference characters. In contrast to control system 290 where secondvalve 256 measures the pressure in removal line 76, in control system294 pressure sensor 252 is coupled with effluent line 78. A signal line254 couples sensor 252 to second valve 256. In this embodiment, secondvalve 256 is set to operate at a pressure differential relative to theset operating pressure of first valve 248. By way of example, wherefirst valve 248 is set to operate 20 psi, second valve 256 may be set tooperate at a pressure of +5 psi relative to the sensed pressure ineffluent line 78. Accordingly, although both valves 248 and 256 measurethe pressure in effluent line 78, a predefined pressure differential ismaintained between the two valves. Although sensors 246 and 252 areshown in FIG. 13 as both being coupled with effluent line 78, in analternative embodiment sensors 246 and 252 can each be coupled withremoval line 76. In one embodiment second valve 256 may be adifferential pressure regulator such as a Fisher 98LD made by FisherControls International, Inc., out of Marshall Town, Iowa.

In yet another embodiment, it is appreciated that first valve 248 incontrol system 294 can be configured such that it does not adjust thepressure on effluent line 78 as the flow rate of fluid passingtherethrough changes. For example, first valve 248 can be configuredsuch that as the amount of exiting light component 243 passingtherethrough decreases, the fluid pressure within effluent line 78 canalso be allowed to decrease. However, since second valve 256 is set tooperate at a pressure relative to the pressure of effluent line 78, theoperating pressure of second valve 256 also decreases, therebymaintaining the desired pressure differential between valves 248 and256.

In yet another embodiment depicted in FIG. 13C, a controller 260 is usedto withdraw the separated fluids from liquid-liquid separator 244.Signals are transmitted from first pressure sensor 246 by use of a firsttransmitter 262 that operates, by way of non-limiting example with a4–20 mA signal. Similarly, first valve 248 transmits a signal by use ofa first I/P converter 264 also with a 4–20 mA signal. First I/Pconverter 264 converts a 4–20 mA control signal to a pneumatic signal inorder to operate first valve 248. Removal line 76 is also configuredwith second pressure sensor 252, a second transmitter 266, a secondvalve 256, and a second I/P converter 268.

According to the present invention, when a load disturbance occurswithin supply stream 30, first pressure sensor 246 and second pressuresensor 252 detect a change in respective pressures between exiting heavycomponent 241 passing through removal line 76 and exiting lightcomponent 243 passing through effluent line 78. According to the presentinvention, such a load disturbance will be noted by controller 260 andrespective valves 248 and 256 will be adjusted in order to maintainboundary line 245 at a preferred distance range away from rotationalaxis 90. According to this embodiment of the present invention, thepressure differential is maintained by the control of first valve 248and second valve 256. Accordingly, the location of boundary line 245 maybe maintained within the preferred distance range away from rotationalaxis 90.

In another configuration for operation, the embodiments depicted inFIGS. 13A, 13B and 13C can be mixed. For example, an alternative systemcould provide first valve 248 on effluent line 78 as discussed abovewith regard to FIG. 13A and second valve 256 on removal line 76 asdiscussed with regard to FIG. 13C. Second valve 256 would be coupledwith the sensor, controller and other electronics as also discussed withregard to FIG. 13C.

Depicted in FIG. 14 is a control system 295 that operates in a slightlydifferent way. Control system 295 includes a valve 296 coupled witheffluent line 78. Valve 296 comprises a ball valve or other type ofvalve which can be fixed to produce a constant defined opening so thatunder normal operating procedures exiting light component 243 is under afirst pressure. As the flow rate changes, however, it is not necessaryfor valve 296 to adjust to maintain the pressure.

Control system 295 also includes a valve 297, such as a solenoid valve,that is designed to selectively fully open and fully close. Valve 297 iselectrically coupled with a sensor 298 that can be coupled with removalline 76 or effluent line 78. Valve 297 is set to fully open and closeover a pressure range. For example, during one mode of operation valve296 is always left open a defined amount while valve 297 is initiallyclosed. When the pressure sensed by sensor 298 reaches a defined upperlimit, as a result of the heavy component collecting within vessel 60,valve 297 is opened allowing the heavy component to exit therethrough.Valve 297 remains open until the pressure sensed by sensor 298 drops toa lower limit at which time valve 297 is closed and the process isrepeated. By controlling valve 297 over a narrow pressure range,boundary line 245 remains relatively constant. In alternativeembodiments, it is appreciated that valves 296 and 297 can be switchedbetween lines 76 and 78. Furthermore, valve 297 can be set to open andclose over a defined time range and/or pressure range.

One feature of one embodiment of the present invention relating tocontrol of the liquid-liquid separation system is the ability toseparate immiscible liquids that have a specific gravity difference ofless than about 5% of each other. The present invention is useful forseparating immiscible liquids that have a specific gravity difference ina range from about 5% to about 0.5%, more preferably from about 4% toabout 0.5%, and most preferably from about 3% to about 0.5%. Of course,the present invention is useful for separating immiscible liquids thathave a specific gravity difference greater than 5%. Where a givenliquid-liquid system is provided such that the specific gravities of thetwo liquids are known, control of such systems is achieved by thepresent invention. Calibration may be conducted for a given rotatingpressurized vessel as disclosed herein. A first rpm may be establishedand various pressure differences noted for different ratios of the twoliquids. A curve may be fitted to these data. Similarly, other rpmamounts may be tested in order to calibrate the rotating pressurevessel. By use of standard control methods such as a PID controller, therpm amount of the rotating pressure vessel may be tracked and theliquid-liquid system separated by maintaining the boundary layer 245within a desired range.

One application of liquid-liquid separator 244 is depicted in FIG. 15.Under certain conditions, environmental discharge regulations mayrequire water to be cleaned of its entrained oil to a level below about100 ppm. According to the embodiment of the present invention depictedin FIG. 15, feed stream 12 comprises substantially no loose particulatematerial except for any incidental trash that may be removed in trashstrainer 18. Supply stream 30 enters liquid-liquid separator 244 and thetwo immiscible liquids are separated as described above.

An exiting heavy component stream 250, which can comprise water in anoil/water system, is feed to a liquid-liquid hydrocyclone 270.Hydrocyclone 270 accomplishes a separation therein that removes more ofthe light component liquid from a concentration above about 100 ppm downto a concentration of less than about 10 ppm.

For example, where an oil/water system is provided, exiting heavycomponent stream 250 comprising the water may have an oil content ofabout 100 ppm. Liquid-liquid hydrocyclone 270 provides a purified heavycomponent liquid stream 272 that has an oil content in a range fromabout 0.1 to about 100 ppm, preferably from about 1 to about 10 ppm, andmore preferably from about 2 to about 5 ppm. A recycle light componentliquid stream 274 is drawn off liquid-liquid hydrocyclone 276 and isblended with flow path 20 to form supply stream 30. Typically, in a50/50 oil/water flow path 20, the content of water within recycle lightcomponent liquid stream 274 will be in a range from about 50% water toabout 80% water. Hydrocyclone 276 can comprise any hydrocyclone know tothose skilled in the art. One example of a hydrocyclone is disclosed inU.S. Pat. No. 5,133,861.

Accordingly, a method of separating a liquid-liquid mixture by use ofseparator 244 depicted in FIG. 11 may include one of the control systemsdepicted in FIGS. 13 and 14 or combination thereof and may additionallyinclude a hydrocyclone that is connected to the heavy component outlet.

Another embodiment of the present invention is depicted in FIG. 16,wherein the more expensive sphere pressure vessel 60 has been replacedwith a double truncated cone pressure vessel 276. FIG. 16 depictsextraction tubes 160 that are longer than their equivalents depicted inFIG. 3. Additionally, a flanged edge 278 of the double truncated cone276 is provided with a bolt 280 in order to assemble double truncatedcone 276. A gasket or an o-ring (not pictured) may be placed betweenmating surfaces of flanged edge 278 in order to achieve a liquid-tightseal that holds under the pressure contemplated for the presentinvention.

FIG. 16 also depicts the axial flow passage 174 to be more angular dueto the shape of double truncated cone 276. One distinction of doubletruncated cone 276 is the absence of a decreasing flow slope. In otherwords, the flow slope along vessel wall 92 is constant for solidparticulate matter or a heavy component liquid as it moves along vesselwall 92 in the direction toward radial extraction tube opening 166.

FIG. 17 is a perspective view of a separator subassembly 292 includingadditional disks 202, 204 along with at least one major disk such ascenter disk 170. FIG. 17 depicts a fin shape for radial fins 184 thatconform with the double truncated cone shape of pressure vessel 276. Anadditional distinction between subassembly 292 and correspondingcomponents in solid-liquid separator 10 is that an extraction tube 160is disposed between each fin 184 in subassembly 292. In this embodiment,underflow passage 190 need not be formed between adjacent flow channels218. According to the present invention, double truncated cone 270depicted in FIGS. 16 and 17 may be used with either a solid-liquidseparator or a liquid-liquid separator.

In yet another embodiment, it is envisioned that a single separator canbe configured to simultaneously separate both two or more immiscibleliquids and particulate matter from a fluid steam. The separator can beconfigured substantially identical to those disclosed in FIGS. 10 and11. In this embodiment, however, the particulate matter collects at thefarthest radial distance from the rotational axis, the lighter of thetwo immiscible liquids collects about the rotational axis, and theheavier of the two immiscible liquids collects between the particulatematter and the lighter liquid. Two separate sets of extractions tubesare used. The first set extends down to the particulate matter forextraction thereof. This is similar to that previously discussed withregard to FIG. 10. The second set of extraction tubes extends to theheavier liquid for extraction thereof. The lighter liquid exits in thesame manner as previously discussed with regard to FIG. 11.

Depicted in FIG. 18 is another alternative embodiment of a separator 300which can Function as a solid-liquid separator and/or a liquid-liquidseparator. Separator 300 comprises a frame assembly 302 which includes ahorizontally disposed base plate 304 and a spaced apart head plate 306in substantially parallel alignment therewith. A cylindrical guard 308extends between base plate 304 and head plate 306 so as to bound acompartment 310. Base plate 304 is supported by a plurality ofadjustable legs 312 downwardly projecting therefrom.

Attached to and extending below base plate 304 is a stationary inlethousing 314. As discussed below in greater detail, a fluid inlet line311 and a fluid delivery line 313 are each fluid coupled with inlethousing 314. Fluid inlet line 311 is used to deliver the fluid that isto separated, clarified, and/or otherwise treated. Accordingly,depending on the configuration and intended use of separator 300, fluidinlet line 311 can comprise flow path 20 or effluent stream 38 ofFIG. 1. Delivery line 313 is used to deliver a fluid to a pressurevessel of separator 300 for use in removing particulate matter collectedwithin the pressure vessel. A valve 317 is coupled with fluid inlet line311 while a valve 319 is coupled with delivery line 313.

A stationary outlet housing 315 is attached to head plate 306 andupwardly extends therefrom. Fluid coupled with outlet housing 315 is aremoval line 347 and an effluent line 348. Removal line 347 is used forthe removal of solids and heavier fluids while effluent line 348 is usedfor removal of the clarified and/or lighter fluids. Shut off valves 349and 351 are coupled with removal line 347 and effluent line 348,respectively.

Rotatably disposed within compartment 310 is a pressure vessel 316having an inlet end 318 and an opposing outlet end 320. As depicted inFIG. 19, pressure vessel 316 is mounted for rotation about a rotationalaxis 466. Pressure vessel 316 includes a peripheral wall 468 having aninterior surface 470 bounding a chamber 472. As previously discussedwith regard to pressure vessel 60, pressure vessel 316 and chamber 472can have a variety of different configurations and can be made of avariety of different materials so as to withstand a desired internalpressure. Although not required, in the embodiment depicted the walls ofpressure vessel 316 slope radially outward toward an equator 474 havinga maximum diameter that encircles rotational axis 466.

A shaft assembly 322, which is also configured to rotate aboutrotational axis 466, extends through and is rigidly coupled withpressure vessel 316. Shaft assembly 322 includes an inlet end 324 thatis rotatably supported within inlet housing 314. Shaft assembly 322 alsoincludes an outlet end 326 that is rotatably supported within outlethousing 315.

Encircling shaft assembly 322 and attached to pressure vessel 316 atinlet end 318 is an annular pulley 328. Returning to FIG. 18, a motor330 is mounted to base plate 304. Motor 330 rotates a drive wheel 332which is also disposed within compartment 310. A belt 334 extendsbetween drive wheel 332 and pulley 328 so as to facilitate rotation ofpressure vessel 316 and shaft assembly 322 relative to stationary inlethousing 314 and stationary outlet housing 315. In this regard, it isappreciated that bearings are disposed between shaft assembly 322 andhousings 314 and 315.

Depicted in FIG. 20, shaft assembly 322 comprises a central manifold336. As depicted in FIG. 22, manifold 336 comprises a substantiallycylindrical collar 337 having an interior surface 338 that extendsbetween an inlet end 340 and an opposing outlet end 342. Radiallyinwardly projecting from interior surface 338 of collar 337 is anannular flange 344. Flange 344 circles a compartment 339. A plurality ofradially spaced apart channels 346 extend through manifold 336 andflange 344 at the outlet side of flange 344. Each channel 346 comprisesa first channel portion 341, a second channel portion 343, and a thirdchannel portion 345, each portion being concentrically disposed andconsecutively constricting toward compartment 339.

An end wall 353 extends across flange 344 on the outlet side of channels346 so as to bound one side of compartment 339. An annular mouth 355projects from end wall 353 and flange 344 toward outlet end 342.Extending between mouth 355 and collar 337 so as to communicate withsecond channel portion 343 of each channel 346 is an annular slot 357.

Returning to FIG. 20, shaft assembly 322 also includes a tubular inputshaft 350. Input shaft 350 extends from a first end 352, whichcorresponds to inlet end 324 of shaft assembly 322, to an opposingsecond end 354. Second end 354 is securely disposed within inlet end 340of manifold 336 so as to bias against flange 344. Input shaft 356 has aninterior surface 360 that bounds a fluid delivery channel 362. Deliverychannel 362 extends from an inlet mouth 364 at first end 352 to channels346 of manifold 336. As depicted in FIG. 19, inlet mouth 364 is insealed fluid communication with a coupling port 365 formed on inlethousing 314. In turn, coupling port 365 is fluid coupled with fluiddelivery line 313 as previously discussed with regard to FIG. 18. Assuch, fluid entering through delivery line 313 passes through inlethousing 314 and into fluid delivery channel 362.

Returning to FIG. 20, input shaft 350 comprises a tubular inner shaft356 and a tubular outer shaft 358 encircling inner shaft 356. Innershaft 356 and outer shaft 358 each extend between first end 352 andsecond end 354. A plurality of radially spaced apart inlet ports 366extend through outer shaft 358 at or toward first end 352. Similarly, aplurality of radially spaced apart outlet ports 368 extend through outershaft 358 at or toward second end 354. An extension tube 370 is coupledwith and radially outwardly projects from each outlet port 368. Formedbetween inner shaft 356 and outer shaft 358 and longitudinally runningfrom inlet ports 366 to outlet ports 368 is a substantially cylindricalfluid inlet channel 372.

As depicted in FIG. 19, outlet ports 368 and extension tubes 370 aredisposed within pressure vessel 316. In contrast, inlet ports 366 are insealed fluid communication with a coupling port 373 formed on inlethousing 314. More specifically, as depicted in FIG. 21, inlet housing314 bounds a cavity 374 that encircles input shaft 350 at inlet ports366. As such, cavity 374 is in fluid communication with inlet ports 366.Cavity 374 has an interior sidewall 375 that spirals so as to radiallyconstrict.

Coupling port 373 extends into inlet housing 314 and connects withcavity 374 at an orientation tangential to cavity 374. In turn, fluidinlet line 311, as previously discussed with regard to FIG. 18, iscoupled with coupling port 373. Accordingly, as fluid enters throughfluid inlet line 311, the fluid passes through cavity 374 and inletports 366 so as to enter fluid inlet channel 372. As a result of thetangential orientation of coupling port 373 and the spiral configurationof cavity 374, the fluid entering cavity 374 is forced to rotate withinannular cavity 374 about rotational axis 466 of shaft assembly 322. Thefluid is rotating in the same direction that shaft assembly 322 rotates.Although not required, this introduction of the fluid in a rotatingorientation minimizes turbulent flow of the fluid passing into separator300, thereby maximizing operating efficiency.

Returning to FIG. 20, similar to input shaft 350, shaft assembly 322also includes a tubular output shaft 376. Output shaft 376 extends froma first end 378 to an opposing second end 380. Second end 380corresponds to outlet end 326 of shaft assembly 322. First end 378 issecurely disposed within outlet end 342 of manifold 336. Output shaft376 has an interior surface 382 that bounds an effluent channel 384.Effluent channel 384 extends from a sealed end wall 386 (FIG. 22) atfirst end 378 to an open exit mouth 388 at second end 380. Furthermore,a plurality of radially spaced apart transfer tubes 400 extend in sealedfluid communication from the exterior of shaft assembly 322 to effluentchannel 384 at first end 378.

As depicted in FIG. 19, transfer tubes 400 are disposed in open fluidcommunication within pressure vessel 316. In contrast, outlet mouth 388is in sealed fluid communication with a coupling port 404 formed onoutlet housing 315. In turn, coupling port 404 is fluid coupled witheffluent line 348 as previously discussed with regard to FIG. 18. Assuch, fluid entering effluent channel 384 through transfer tubes 400,exits through outlet housing 315 and effluent line 348.

Returning to FIG. 20, output shaft 376 also comprises a tubular innershaft 390 and a tubular outer shaft 392 encircling inner shaft 390.Inner shaft 390 and outer shaft 392 each extend between first end 378and second end 380. First end 378 of inner shaft 390 is received withinmouth 355 of manifold 336 so as to bias against end wall 353. An annularseal 359 extends between inner shaft 390 and mouth 355.

A plurality of radially spaced apart removal ports 394 extend throughouter shaft 392 at or toward second end 380. Formed between inner shaft390 and outer shaft 392 and longitudinally running from annular slot 357formed on manifold 336 to removal ports 394 is an annular channel 395.Channel 395 and annular slot 357 combine to form a removal channel 396that extends from each channel 346 on manifold 336 to removal ports 394.

As depicted in FIG. 19, removal ports 394 are in sealed fluidcommunication with a coupling port 402 formed on outlet housing 315. Inone embodiment, coupling port 402 communicates with removal ports 394 insubstantially the same fashion that inlet ports 366 fluid couple withcoupling port 373, as discussed above with regard to FIG. 21, exceptthat the fluid is flowing in the opposite direction. Coupling port 402is fluid coupled to removal line 347, as discussed with regard to FIG.18, such that fluid and/or particulate matter entering removal channel396 exits through removal ports 394, coupling port 402 and removal line347.

Depicted in FIG. 20, an extraction tube 410 is fluid coupled with andradially outwardly projects from each channel 346 of manifold 336. Asdepicted in FIG. 23, each extraction tube 410 comprises an outer tube412 having an interior surface 414 extending between a first end 416 andan opposing second end 418. Disposed within outer tube 412 is an innertube 420. Inner tube 420 has an exterior surface 422 and an interiorsurface 424 each extending between a first end 426 and an opposingsecond end 428. First end 426 of inner tube 420 projects past first end416 of outer tube 412. Interior surface of 424 of inner tube 420 boundsa supply duct 430. A removal duct 432 is bound between interior surface414 of outer tube 412 and exterior surface 422 of inner tube 420.

As depicted in FIG. 22, first end 426 of inner tube 420 of eachextraction tube 410 is secured in fluid communication within thirdchannel portion 345 of a corresponding channel 346 of manifold 336. Assuch, supply duct 430 is in fluid communication with compartment 339 ofmanifold 336 and fluid delivery channel 362. Furthermore, first end 416of outer tube 412 of each extraction tube 410 is secured in fluidcommunication within first channel portion 345 of a correspondingchannel 346 of manifold 336. As such, each removal duct 432 is in fluidcommunication with second channel portion 343 of a corresponding channelportion 346 which in turn is in fluid communication with effluentchannel 384 by way of annular slot 357 in manifold 336.

Returning to FIG. 23, each extraction tube 410 also includes a nozzle436. Nozzle 436 comprises a tubular stem 438 having an interior surface440 and an exterior surface 442 each extending between a first end 444and an opposing second end 446. Radially outwardly projecting fromsecond end 446 of stem 438 is an annular flange 448. Second end 428 ofinner tube 420 is securely disposed within stem 438 while second end 418of outer tube 412 is securely disposed about the exterior of stem 438. Aplurality of radially spaced apart slots 445 extend through outer tube412 at second end 418. Slots 445 are in substantially parallel alignmentwith the rotational axis of outer tube 412. As a result, at least aportion of each slot 445 forms a channel extending from the exterior toremoval duct 432. In one embodiment, each slot 445 is oriented so as totangentially intersect with removal duct 432.

An annular sidewall 450 forwardly projects from the outer edge of flange448. In turn, an annular lip 452 forwardly projects from the terminalend of sidewall 450. Secured inside of annular lip 452 so as to biasagainst sidewall 450 is an end cap 454. In this configuration, a diskshaped compartment 456 is encircled by sidewall 448 and bounded betweenend cap 454 and flange 448. Compartment 456 is in fluid communicationwith supply duct 430.

Depicted in FIG. 24, sidewall 450 and lip 452 share a common outer face458. Outer face 458 comprises six flat faces 460 each having a notch 462formed thereon. A flush port 464 linearly extends from each notch 462 tocompartment 456 by passing through sidewall 450. Each flush port 464 isconfigured to intersect tangentially with interior surface 451 ofsidewall 450. As a result, fluid exiting through flush ports 464 exitsat a generally tangential orientation to a radial arc from the center ofnozzle 436. This is in contrast to the fluid exiting radially from flushports 464. In view of the forgoing, fluid traveling down supply duct 430passes through compartment 456 and out through flush ports 464. Thefluid can then enter removal duct 432 through slots 445.

As illustrated in FIG. 22, nozzle 436 is disposed adjacent to ordirectly against the interior of wall 468 of pressure vessel 316 atequator 474. As will be discussed below in greater detail, nozzle 436can be further spaced radially inward from wall 468 but in someembodiments such positioning may be less efficient in removingparticulate matter.

As with pressure vessel 60, pressure vessel 316 is also configured witha plurality of fins and discs for channeling fluid through vessel 316.An annular first disc 478 encircles input shaft 350, and is secured,such as by pins, bolts, welding and the like, to inlet end 340 ofmanifold 336. Similarly, an annular second disc 480 encircles outputshaft 376 and is secured to outlet end 342 of manifold 336. Each ofdiscs 478 and 480 is positioned perpendicular to rotational axis 466.

Intersecting with discs 478 and 480 are a plurality of fins 482. Asdepicted in FIG. 25, each fin 482 comprises a inside edge 484 thatextends between a first end 486 and an opposing second end 488 and aremaining perimeter edge 490. Inside edge 484 is configured tocomplementary fit over manifold 336 and is configured to run in parallelalignment with rotational axis 466. Perimeter edge 490 is configuredsubstantially complementary to interior surface 470 of pressure vessel316.

As depicted in FIGS. 22 and 25, perimeter edge 490 comprises a first cutout portion 492 at first end 486. First cut out portion 492 is formedradially out from the terminal end of extension tubes 370. As a result,an annular inflow equalizing channel 494 circles shaft assembly 322within chamber 472 and is partially bounded between first cutout portion492 of each fin 482 and interior surface 470 of pressure vessel 316.

Perimeter edge 490 of each fin 480 also comprises a second cut outportion 496 at second end 488. Second cut out portion 496 is formedradially out from transfer tubes 400. As a result, an annular outflowequalizing channel 498 circles shaft assembly 322 within chamber 472 andis partially bounded by second cutout portion 496 of each fin 482,interior surface 470 of pressure vessel 316, and output shaft 376.

Extending from inside edge 484 of each fin 482 are a pair of spacedapart disc receive slots 500. Complementary radially spaced apart slotsare also formed on the outside edge of discs 478 and 480 so, as depictedin FIG. 26, fins 482 and discs 478, 480 can be interlocked together bycoupling the slot. This is the same form of interlocking as previouslydiscussed with regard to that fins and discs in FIG. 5. Fins 482 arethus secured to shaft assembly 322 and extend in parallel alignment withrotational axis 466. Bounded between each adjacent pair of fins 482 andextending between inlet end 318 to outlet end 320 is a flow channel 502.

As further depicted in FIGS. 22 and 26, where separator 300 is primarilybeing used separate fluids of different densities, such as oil andwater, discs 478 and 480 are form with openings 504 that extendtherethrough in alignment with each fluid channel 502. Openings 504allow the fluid to flow through the discs as opposing to having to flowaround them. In this embodiment, discs 478 and 480 primarily function assupports for fins 482.

Depending on its intended use, the operation of separator 300 is similarto the operation of separator 10 and separator 244 as previouslydiscussed. As such, the operating parameters previously discussed withregard to separators 10 and 244 are also applicable to separator 300.Returning to FIG. 18, during operation motor 330 is activated causingrotation of pressure vessel 316 about rotational axis 466. Shaftassembly 322, extraction tubes 410, and fins 482 with associated discsrotate concurrently with pressure vessel 316. A feed stream 506 is feedinto separator 300 through inlet line 311. Feed stream 506 is preferablypressurized, such as by pump 80 in FIG. 2, so that feed stream 506 ismaintained under a predefined pressure within pressure vessel 316 duringoperation of separator 300.

With discs 478 and 480 having openings 504 therein (FIG. 26), separator300 is configured to primarily operate as a liquid-liquid separator. Assuch, for purposes of illustration feed stream 506 comprises at leasttwo immiscible liquids of different density. The two liquids are againreferred to as heavy component 241 and light component 243. Theoperation of separator 300 will be discussed with regard to separatingthe two components. Although separating of the two components can alsofacilitate at least some removal of particulate matter from lightcomponent 243, a later embodiment will be discussed with regard tooperating separator 300 has a solid-liquid separator for removingparticulate matter.

As illustrated in FIG. 19, feed stream 506 passes from inlet line 311(FIG. 18) into coupling port 373 of inlet housing 314. As previouslydiscussed with regard to FIG. 21, feed stream 506 is forced to spinwithin cavity 374 so as to at least being matching the rotation of feedstream 506 with the rotation of shaft assembly 322. Spinning feed stream506 next passes through inlet ports 366 and into fluid inlet channel 372of input shaft 350. Feed stream 506 exits inlet channel 372 throughextension tubes 370, thereby entering chamber 472 of pressure vessel316. Although not required, in one embodiment the feed stream is nowrotating at substantially the same speed as pressure vessel 316. The useof extension tubes 370 which radially outwardly extend from shaftassembly 322 forces inlet steam 506 exiting therefrom to be subject toat least a portion of the gravitational force produced by separator 300.In alternative embodiments, extension tubes 370 can be removed.

As depicted in FIG. 22, upon entering pressure vessel 316 thecentrifugal force imposed due to the rotation of pressure vessel 316pushes the stream radially outwardly towards wall 468. As the streamenters pressure vessel 316, it enters one of the flow channels 502 (FIG.26) and proceeds to fill vessel 316. As previously discussed, flowchannels 502 help to eliminate the Coriolis effect. Although anextension tube 370 can be provided for each discrete flow channel 502,inflow equalizing channel 494 allows fluid communication at the entranceof flow channels 502, thereby helping to ensure a common fluid level andflow rate through each flow channel 502. In alternative embodiments,inflow equalizing channel 494 can be eliminated.

As feed stream 506 travels within flow channels 502 toward transfertubes 400, the stream is subjected to the tremendous centrifugal forcesimposed on it due to the rotation of vessel 316. Thus, the more densecomponent of the stream flows radially outwardly while the less densecomponent flows radially inwardly toward rotational axis 466. A boundaryline 508, disposed parallel to rotational axis 320, is thus formedwithin chamber 472 denoting the separation between heavy component 241and light component 243.

Light component 243 continues to travel within flow channels 502 totransfer tubes 400. The formation of outflow equalizing channel 498allows fluid communication between each stream of light component 243leaving its corresponding flow channel 502, thereby helping to ensure acommon inflow through each of transfer tubes 400. As a result, there canbe fewer transfer tubes 400 than flow channels 502. Alternatively, atransfer tube 400 can be provided for each flow channel 502, therebyeliminating the need for outflow equalizing channel 498.

Returning to FIG. 19, light component 243 enters effluent channel 384through transfer tubes 400. Lighter component 243 subsequently exitseffluent channel 384 and separator 300 through effluent line 348 (FIG.18) as either a final product or for subsequent processing.

Returning back to FIG. 22, heavy component 241 is removed from vessel316 by being drawn into removal duct 432 of each extraction tube 410through slots 445 at the end thereof. In this regard, slots 445 can bepositioned at any location radially out from boundary line 508. Heavycomponent 241 travels radially inward along removal ducts 432 where itsubsequently passes through second channel portion 343 and into removalchannel 396 by way of annular slot 357. In turn, heavy component 241exits removal channel 396 and separator 300 by way of removal ports 394and removal line 347. The removal of heavy component 241 and lightcomponent 243 is controlled using one of the control systems and methodsas previously discussed with regard to FIGS. 13-14 so that boundary line508 is maintained at a desired location or within a desired range withinvessel 316.

In one embodiment, it is appreciated that an extraction tube 410 can beprovided for each flow channel 502. In an alternative embodiment, anextraction tube 410 can be provided in every other flow channel 502 orin any other desired placement. Where an extraction tube 410 is notprovided in each channel 502, some form of opening or gap is provided atthe separating fin so that fluid communication of the heavy component241 is provided between two or more flow channels 502. Such openings orgaps can be formed by underflow passage 190 as previously discussed.

It is appreciated that most fluids for which separation of thecomponents is desired will also include some form of particulate matter.The particulate matter which is initially suspended within feed stream506 enters flow channels 502 where under the gravitational forceproduced by separator 300 is forced to the interior of wall 468primarily about equator 474. Periodically the collected particulatematter is removed from vessel to prevent an overbuild up within vessel316.

By way of example, at periodic intervals valves 317 and 351 on fluidinlet line 311 and effluent line 348, respectively, are closed.Subsequently, valves 319 and 349 on delivery line 313 and removal line347, respectively, are opened. Next, with vessel 316 still rotating, acleaning stream 510 is pumped into delivery line 313. Cleaning stream510 travels down delivery channel 362 where is subsequently passes intosupply duct 430 of each extraction tube 410. Finally, cleaning stream510 passes through flush ports 464 into chamber 472 of pressure vessel316. As a result of the orientation of flush ports 464, the exitingcleaning stream 510 produces a swirling vortex around nozzle 436. Theswirling vortex resuspends the particulate matter that has caked orotherwise deposited against the interior of wall 468. Simultaneouslywith delivering cleaning stream 510 into chamber 472, heavier component241 now having the particulate matter suspended therein is drawn outthrough removal ducts 432 in extraction tubes 410 as previouslydiscussed.

Once a desired amount particulate matter and heavy component 241 isremoved, valves 319 and 349 on delivery line 313 and removal line 347,respectively, are closed. Valves 317 and 351 on fluid inlet line 311 andeffluent line 348, respectively, continue to remain closed for asufficient period of time to enable the resuspended solids to againsettle against the interior of wall 468 as a result of the rotation ofpressure vessel 316. Although not required, this act helps to ensurethat resuspended solids are not dawn out with the lighter component.Once the solids have again settled, valves 317 and 351 are opened andthe process is continued. In yet another method of operation, it isappreciated that feed stream 506 and cleaning stream 510 can feedsimultaneously for concurrently removing both the heavier component andthe lighter component.

In alternative embodiments, it is appreciated that extraction tube 410can have a variety of different configurations. For example, flush ports464 can be positioned at any orientation including radially outward.Furthermore, flush ports 464 can be positioned to exit through end cap454. Any of a number of other configurations for nozzle 436 in whichfluid can be ejected therefrom for resuspension of the particulatematter can also be used.

In yet another embodiment as depicted in FIG. 27, an extraction tube 514is shown without the use of nozzle 436. Extraction tube 514 has an innertube 516 bounding a supply duct 518 and a surrounding outer tube 520. Aremoval duct 522 is bound between inner tube 516 and outer tube 520.Each of tubes 516 and 518 extends between a first end 524 and anopposing second end 526. First end 524 of extraction tube 514 is coupledwith manifold 316 in substantially the same way as extraction tube 410.

Second end 526 of each of tubes 516 and 520 are openly exposed asopposed to being coupled with nozzle 436. As such, fluid simply exitsthrough supply duct 518 at second end 526 to resuspend the solidssettled against pressure vessel 316 while the heavier component with theresuspended solids therein enters into removal duct 522 at second end526. In this embodiment, outer tube 520 can be formed without slots 445.If desired, however, a support collar (not shown) having holes extendingtherethrough can be positioned between inner tube 516 and outer tube 520to maintain spacing between the tubes. It is also appreciated that thesystem can be manipulated so that cleaning stream 510 flows out ofremoval duct 522 into pressure vessel 316 while the heavy component 241with the resuspended particulate matter is removed through supply duct518.

Depicted in FIG. 28 is another embodiment of an extraction tube 530.Extraction tube 530 comprises an integral tube 532 that bounds a supplyduct 534 and an adjacently disposed removal duct 536. It is appreciatedthat one skilled in the art based on the teaching herein could modifymanifold 336 to couple with a first end of extraction tube 530 so thatsupply duct 534 communicates with delivery channel 362 and removal duct536 communicates with removal channel 396. Alternatively extraction tube530 can also comprise two separate tubes, one that bounds supply duct534 and one that bounds removal duct 536.

Further alternative embodiments of extraction tubes are disclosed inU.S. Pat. No. 5,853,266, entitled Fluidising Apparatus which drawingsthereof and disclosure set forth in the Detailed Description of theInvention are incorporated herein by specific reference. Various formsof extraction tubes can also be obtained from Merpro Limited out ofNailsea, Bristol, United Kingdom.

Although the above described embodiment of separator 300 can be used forthe removal of some particulate matter, the configuration is primarilydesigned for separation of mixed liquids, i.e., separating oil andwater. As previously discussed, however, separator 300 can also functionprimarily as a solid-liquid separator. Under this embodiment it isdesirable to maximize the application of the centrifugal force on theparticulate matter within the fluid. Accordingly, depicted in FIG. 29, afin assembly is shown wherein each of the fins 482 interlock with afirst disc 538 and a second disc 540 in substantially the same way thatdiscs 478 and 480 interlocked with fins 482 in FIG. 25. One distinctionbetween discs 538, 540 and discs 478, 480 is that discs 538, 540 do nothave large openings 504 extending therethrough. In one embodiment,however, one or more small gas ports 542 do extend through each of discs538 and 540 adjacent to their inside perimeter edge.

Turning to FIG. 22, assuming that discs 478 and 480 were replaced withdiscs 538 and 540, respectively, the fluid entering chamber 472 ofpressure vessel 316 through extension tubes 370 is forced to initiallytravel around the outer perimeter of disc 538. In so doing, the fluidand particulate matter therein are subject to a greater centrifugalforce than if they had simply passed through openings 504. The increasedcentrifugal force results in a higher concentration of the particulatematter settling against interior surface 470 of pressure vessel 316primarily about equator 474. The clarified liquid is removed frompressure vessel 316 through transfer tubes 400 as previously discussedwhile the solids are periodically resuspended and removed throughextraction tube 410 or the alternatives discussed therewith as alsopreviously discussed. In one embodiment separator 300 can be operatedusing the method and valve assembly as discussed with regard tosolid-liquid separator 10.

Any gas which enters vessel 316 passes through gas ports 542 and exitswith the clarified liquid. Alternatively, the gas can be removed fromthe feed stream before it enters the separator by passing the streamthrough a commercially available needle valve or other device designedto remove gases from fluid streams. In this embodiment, gas ports 542are note required.

One of the benefits of having disc 540 solid, thereby requiring all ofthe fluid to pass around the outer perimeter thereof, is that it extendsthe retention time of the fluid within pressure vessel 316. In general,the longer the retention time the more particulate matter is separatedfrom the fluid. In alternative embodiments, however, first disc 538 canbe solid while second disc 540 can have openings 540 formed therein.

The present invention may be embodied in other specific forms withoutdeparting from its spirit of essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. A separator comprising: a vessel having a peripheral wall bounding achamber, the vessel being rotatable about a rotational axis extendingthrough the vessel, the chamber communicating with an inlet and a firstoutlet; a plurality of fins disposed within the chamber; a second tubeextending from toward the rotational axis to toward the peripheral wall,the second tube having a first end in fluid communication with theexterior of the vessel and an opposing second end bounding a secondoutlet, the first outlet being disposed closer to the rotational axisthan the second outlet such that during use a fluid boundary line can beformed between the first outlet and the second outlet; and a first tubeextending from toward the rotational axis to toward the peripheral wall,the first tube being coupled with a fluid source for selectivelydispensing a fluid stream at or adjacent to the peripheral wall.
 2. Aseparator as recited in claim 1, wherein one of the first tube and thesecond tube is disposed within the other.
 3. A separator as recited inclaim 1, wherein the first tube and the second tube are spaced apart. 4.A separator as recited in claim 1, wherein the first tube and the secondtube are integrally formed.
 5. A separator as recited in claim 1,wherein the first tube from defines and extends along a longitudinalaxis, and the longitudinal axis of the first tube intersects therotational axis.
 6. A separator as recited in claim 1, wherein the firsttube and the second tube combine to form an extraction tube, theseparator further comprising a plurality of extraction tubes extendingfrom toward the rotational axis to toward the peripheral wall.
 7. Aseparator as recited in claim 1, wherein the second tube is alsoconfigured to withdraw fluid from the chamber of the vessel.
 8. Aseparator as recited in claim 1, wherein the plurality of fins arespaced apart and extend from toward the rotational axis to toward theperipheral wall.
 9. A separator as recited in claim 8, wherein each ofthe fins is disposed in a corresponding plane that is aligned with oroffset from the rotational axis.
 10. A separator as recited in claim 1,further comprising a first disc disposed within the chamber, the firstdisc outwardly projecting so as to intersect with each of the pluralityof fins.
 11. A separator as recited in claim 10, wherein the first discradially outwardly projects in substantially perpendicular alignmentwith the rotational axis.
 12. A separator as recited in claim 1, furthercomprising a plurality of perforations extending through the first disc.13. A separator as recited in claim 1, wherein the first disc isdisposed adjacent to the first tube.
 14. A separator as recited in claim1, further comprising a plurality of spaced apart discs disposed withinthe chamber, each disc radially outwardly projecting from toward therotational axis to toward the peripheral wall so as to intersect witheach of the plurality of fins.
 15. A separator as recited in claim 1,wherein each of the plurality of fins has an outer edge, at least aportion of each outer edge being disposed adjacent to the peripheralwall so as to form a plurality of discrete flow channels.
 16. Aseparator as recited in claim 15, further comprising: the vessel havingan equator with a maximum diameter encircling the rotational axis; and apassage extending between at least two of the discrete flow channels atthe equator.
 17. A separator according to claim 1, wherein the chamberhas a substantially spherical configuration or the configuration of adouble truncated cone.
 18. A separator as recited in claim 1, furthercomprising a pressure actuated valve regulating the flow of fluidexiting through the first outlet.
 19. A separator as recited in claim 1,further comprising: a first valve regulating the flow of fluid exitingthrough the first outlet; a second valve regulating the flow of fluidexiting through the second outlet; a first pressure sensor disposed tosense the fluid pressure upstream of the first valve; and a secondpressure sensor disposed to sense the fluid pressure upstream of thesecond valve.
 20. A separator as recited in claim 19, wherein the firstvalve and the second valve are configured to maintain a pressuredifferential therebetween.
 21. A separator as recited in claim 19,further comprising a controller in electrical communication with thefirst valve, the second valve, the first pressure sensor, and the secondpressure sensor.
 22. A separator as recited in claim 1, wherein theinlet is disposed at a first end of the vessel and the first outlet isdisposed on an opposing second end of the vessel.
 23. A separatorcomprising: a vessel having a peripheral wall bounding a chamber, thevessel being rotatable about a rotational axis extending through thevessel, the chamber communicating with an inlet and a first outlet; atubular member disposed within the chamber and communicating externalthereof; a plurality of fins disposed within the chamber, each of thefins extending from toward the tubular member to toward the peripheralwall; and a first tube projecting from the tubular member to toward theperipheral wall, the first tube having a second outlet in communicationwith the chamber, the first outlet being disposed closer to therotational axis than the second outlet such that during use a fluidboundary line can be formed between the first outlet and the secondoutlet.
 24. A separator as recited in claim 23, wherein each of theplurality of fins is disposed in a corresponding plane that intersectswith and is in longitudinal alignment with the tubular member.
 25. Aseparator as recited in claim 23, further comprising a second tubeextending from at least toward the tubular member to toward theperipheral wall, the second tube being coupled with a fluid source forselectively dispensing a fluid stream at or adjacent to the peripheralwall.
 26. A separator as recited in claim 25, wherein one of the firsttube and the second tube is disposed within the other.
 27. A separatoras recited in claim 25, wherein the first tube and the second tube arespaced apart.
 28. A separator as recited in claim 25, wherein the firsttube and the second tube are integrally formed.
 29. A separator asrecited in claim 25, wherein the first tube and the second tube combineto form an extraction tube, the separator further comprising a pluralityof extraction tubes extending from toward the rotational axis to towardthe peripheral wall.
 30. A separator as recited in claim 25, wherein thesecond tube is also configured to withdraw fluid from the chamber of thevessel.
 31. A separator as recited in claim 23, wherein the first tubefrom defines and extends along a longitudinal axis, and the longitudinalaxis of the first tube intersects the rotational axis.
 32. A separatoras recited in claim 23, wherein each of the fins is disposed in acorresponding plane that is aligned with or offset from the rotationalaxis.
 33. A separator as recited in claim 23, further comprising a firstdisc disposed within the chamber, the first disc outwardly projecting soas to intersect with each of the plurality of fins.
 34. A separator asrecited in claim 33, wherein the first disc radially outwardly projectsin substantially perpendicular alignment with the rotational axis.
 35. Aseparator as recited in claim 33, further comprising a plurality ofperforations extending through the first disc.
 36. A separator asrecited in claim 23, wherein the first disc is disposed adjacent to thefirst tube.
 37. A separator as recited in claim 23, further comprising aplurality of spaced apart discs disposed within the chamber, each discradially outwardly projecting from toward the rotational axis to towardthe peripheral wall so as to intersect with each of the plurality offins.
 38. A separator as recited in claim 23, wherein each of theplurality of fins has an outer edge, at least a portion of each outeredge being disposed adjacent to the peripheral wall so as to form aplurality of discrete flow channels.
 39. A separator as recited in claim38, further comprising: the vessel having an equator with a maximumdiameter encircling the rotational axis; and a passage extending betweenat least two of the discrete flow channels at the equator.
 40. Aseparator according to claim 23, wherein the chamber has a substantiallyspherical configuration or the configuration of a double truncated cone.41. A separator as recited in claim 23, further comprising a pressureactuated valve regulating the flow of fluid exiting through the firstoutlet.
 42. A separator as recited in claim 23, further comprising: afirst valve regulating the flow of fluid exiting through the firstoutlet; a second valve regulating the flow of fluid exiting through thesecond outlet; a first pressure sensor disposed to sense the fluidpressure upstream of the first valve; and a second pressure sensordisposed to sense the fluid pressure upstream of the second valve.